Wednesday, 11 June 2014

How to diagnose MacBook battery problems

Problems with MacBook batteries include the MacBook not lasting as long as it once did on a full charge, or the MacBook switching itself off seemingly randomly even if the battery appears to indicate a useful charge.

Diagnosing problems

Battery Status menu

Your MacBook constantly monitors the health of its battery and a quick way to view the current status is to hold down the Alt/Option key and click the battery charge icon at the top right of the desktop near the clock. After the Condition heading at the top of the menu you’ll see one of four battery status messages: Normal, Replace Soon, Replace Now, and Service Battery.

It should be obvious that Normal indicates a healthy battery. Perhaps surprisingly, Replace Soon is a mere warning rather than a demand and your MacBook should still function correctly on battery power, albeit with noticeably shorter battery life than when it was new.

However, the last two statuses – Replace Now and Service Battery – are indications that the battery is near dead.

CoconutBattery allows you to dig-down into technical details for more information.

Apps like the free CoconutBattery let you dig-down into technical details to get more detailed information. Apple doesn’t explain how it generates the battery life status reading but it’s probably divined by measuring the maximum charge the battery can currently hold against its original capacity when new. CoconutBattery will display both these figures, measured in milliamp hours (mAh). A MacBook Pro that had an original design capacity of 5,400mAh and now stores only 3,700mAh has lost just over 30% of its capacity, for example. However, the MacBook will still report the battery is charged 100%. It just won’t last as long as it once did, and a Replace Soon status message will almost certainly appear.

Another figure worth noting within CoconutBattery is the Loadcycles figure, which is also known as the charge cycles figure. This measures how many times 100% of the battery charge has been used-up. This is important because during each charge cycle the battery loses a small fraction of its ability to hold charge, which is what causes the capacity to drop over time. It should be noted that a charge cycle doesn’t necessarily mean entirely running out of juice from a full charge. Using 50% of the battery life one day before recharging and using 50% the next day will mean one charge cycle has been notched-up. Thus, you will consume charge cycles even if your MacBook is mostly plugged in, with only the occasional hour or two on battery power.

What Apple says

Apple says its MacBook range retain 80% of their charge capacity after 1000 charge cycles, and that’s been the case with most models since 2009. After this Apple considers a battery to be “consumed”, and this is the point at which you may start to notice problems, if not battery status warnings.

If your MacBook is still within warranty (or covered by AppleCare) and you’re experiencing problems while the cycle count is significantly below 1000 then you should book an appointment with an Apple genius because the battery may have a manufacturing defect. Note that the charge indicator seemingly getting stuck at anywhere between 93-99% charge isn’t a fault. This is just how MacBook batteries work.

Storing a MacBook fully charged for a prolonged length of time without use can permanently reduce the overall charging capacity. Storing a MacBook fully discharged can lead to what Apple calls a deep discharge state, which might make it impossible to charge the battery in future. To avoid either situation try to store your MacBook 50% charged, and shutdown before storing it, rather than letting it go into sleep mode.

Replacing a battery

Before purchasing a replacement battery you might want to reset the System Manager Controller (SMC). This returns hardware settings to default values and causes your MacBook to re-evaluate the battery from scratch. This removes the risk of an incorrect status.

Apple offers a battery replacement service for most recent models of MacBook, and prices are reasonable, but replacement batteries are available from a number of third-parties if you fancy saving money by doing it yourself. Be sure to buy only a genuine Apple part because faulty batteries can explode or catch fire. Sadly, the most faithful indicator of quality is price and genuine parts are usually the most expensive.

Whether the battery is user-replaceable depends on when it was manufactured, and you’ll have better luck if your MacBook is older. For example the early Intel MacBooks, such as the white or black range, featured batteries that could be replaced by simply turning a clearly-marked screw on the bottom of the unit (usually a coin can be used for this purpose), or by releasing catches.

Unfortunately, with most of the aluminium “unibody” MacBook range, including the MacBook Pro, Apple dropped the ability for users to be able to replace the battery. Doing so is still possible although involves removing the bottom panel of the MacBook, then unscrewing the battery fixings and detaching a cable from the motherboard. For anybody who’s ever delved inside a PC this isn’t difficult but it’s not a task for beginners, and will probably require a specialist pentalobe or twi-wing screwdriver, depending on the model of MacBook. The popular iFixIt site not only provides free battery replacement guides for most models of MacBookbut also sells the necessary tools and parts.

With all MacBook Air models the batteries are difficult to handle once removed because the cells aren’t enclosed in hard plastic, as with earlier MacBook models. Therefore, user replacement isn’t advised. Additionally, with the 13 and 15in Retina-based MacBook Pro range as of 2012 Apple began gluing batteries into place, making it both difficult and dangerous to remove them because of the risk of puncturing or tearing, in which case the battery may explode or release noxious fumes.

Can I replace my MacBook battery?

The table below indicates the feasibility of replacing a MacBook’s battery. Note that Unibody models are those famously created from a single piece of aluminium, as opposed to those made from plastic or individual aluminium components. To find out the model of your MacBook, click the Apple menu, then About This Mac. In the window that appears, click the More Information button.

Not user replaceable without removing bottom panel, removing battery connector, and unscrewing battery fixings. Note MacBook Air batteries are dangerous to handle because of largely unprotected battery cells that should not be compressed or bent